A radio frequency (RF) amplifier is an important part in an RF transmitter circuit. Its main function is to amplify the signal power and transmit the amplified signal to an antenna, so that the antenna can radiate the signal to a remote RF receiver. Since an RF power element in the RF amplifier is the most power-consuming part in the RF transmitter circuit and directly decides the quality of the transmitted signal, so design goals of the RF power element include output power, distortion, efficiency, bandwidth, and reliability.
A conventional RF amplifier is limited to the low-voltage and high-current construction as which is the general manufacturing process for an RF power element. Therefore, the high-wattage RF power element normally utilizes a traditional parallel distributed structure to reduce current and distribute heat sources. In addition, the RF amplifier system is affected by other parasitic elements, so it normally adopts a large-size heat dissipation plate, which making the entire RF amplifier become too heavy. Moreover, the current RF power element also has a disadvantage of slow thermal equilibrium, and as a result, users need to wait a longer time for the system to warm up.
The use of the conventional RF power element in the conventional RF amplifier system has disadvantages such as low conversion efficiency and too many components. In solution, industries have developed a new high-voltage RF power switch element to constitute the RF power amplifier. However, the new RF power switch element has high power dissipation per unit volume, and the heat source is concentrated, so heat dissipation is required so as to achieve stable temperatures and avoid damages due to high temperatures.
Accordingly, the inventor made various studies to overcome the above-mentioned problems, on the basis of which the present invention is accomplished.